Wild Barcelona: Flights of fancy

Bright as plasticine, an insect clings to the seed pod, munching on a fly. A long yellow abdomen sticks out straight behind like a windsock, and great globular eyes match the colour of the sky. Many more are spread over the hillside: flocks of red-veined darters, out to graze.

These young dragonflies bring colour to the bleached, late-summer landscape of Collserola. After weeks of scorching sun and cloudless skies, even the thistles are brown and petrified. One of the few plants in flower is vervain­­— the sacred herb—producing miniscule violet specks on the tip of long stems. Only the umbrella pines look green and fresh. But for the moment the darters don’t need any water, just plenty of flies.

Anchored to stems and twigs, the dragonflies are immobile except for sudden deft movements of the head as they scan for food. A quick foray, an insect plucked, and they return to their spot to chew on their catch. Their six legs, used to grip the perch, are transformed in flight into a spiny basket, in which the prey finds itself trapped.

The days pass and maturity seeps visibly through the young males, as their bodies and wing veins acquire the deep red of adulthood. The females remain a vivid yellow, striped with black. Once fed and grown, the red-veined darters will abandon the feeding pastures of Collserola and head for a source of water to mate and lay eggs, the last stage of their lives.

Many people are slightly afraid of dragonflies. Folktales have them working for the devil, sewing up the eyes of naughty children or weighing up souls. They’re also known as mischief-makers—the Norwegians call them ‘eye-pokers’. But these zesty technicolour beasts can’t sting and will cling peacefully to your finger. In self-defence the most they will do is give you a nip.